#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
#include <cstdio>
#include <string>
#include <stack>
#include <set>
#define IOS ios::sync_with_stdio(false), cin.tie(0)
using namespace std;
typedef long long ll;
ll dp[50];
ll f(ll n){
    if(dp[n]>0)return dp[n];
    ll sum=0;
    for(ll k=2;k<n;k++){
        sum+=f(k)*f(n-k+1);
    }
    dp[n]=sum;
    return sum;
}
int main()
{
    IOS;
    dp[2]=dp[3]=1;
    ll n;
    while(cin>>n){
        cout<<f(n)<<endl;
    }    
    getchar();
    getchar();
    return 0;
}
